<?php
/**
 * Created by PhpStorm.
 * User: Fm_Strip.lue
 * Date: 2017/6/7
 * Time: 11:11
 */
//从数组变量$arr中，读取键为0的值
$arr = array('苹果','香蕉');

if( isset($arr0) ) {print_r($arr0);}
echo $arr[0];